Hammer unions are commonly employed to join pipe segments together. Typically, the wing nut component of the hammer union, which has a wing nut pipe segment with a threaded wing nut having integrated lugs, is tightened onto a male threaded pipe component by hammering upon the lugs. When the wing nut becomes unusable, it is usually necessary to remove the entire wing nut pipe segment from service.
It is standard practice to capture the wing nut on the wing nut pipe segment which prevents users from removing or replacing the wing nut. Once captured, the wing nut and the wing nut pipe segment are generally inseparable.
Often, before the full, useful life of the wing nut pipe segment is reached, one or more lugs on the wing nut will become deformed. A wing nut with one or more deformed lugs cannot reliably be mated to a male threaded piece of piping equipment. The piping equipment, however, would generally still be usable if the wing nut is replaced. At this time, there is no safe, field-installable wing nut that can be used to replace deformed, damaged or worn-out wing nuts which are captured on the wing nut pipe segment.
Currently, when a wing nut becomes deformed due to damaged or deformed lug(s), the end of the wing nut pipe segment on which the wing nut is installed is cut off, the deformed wing nut is replaced with a new wing nut, and the pipe is machined and welded together. Unfortunately, this repair approach often has quality problems. These quality problems lead to safety issues.
Safety of a joined hammer union is a major concern because hammer unions are often used to connect piping carrying large volumes of fluid under high pressures. Due to the internal forces on the pipe joint, hammer union joints commonly fail in an explosive manner. A misaligned wing nut on a hammer union joint may hold pressure for a period of time, but may ultimately fail as the pressure pushes against the joint.
An attempted field repair of a wing nut using common cutting and welding techniques creates a significant risk for misaligned or poorly welded joints. In normal field situations, there are few or no field personnel qualified to perform the highly skilled welding and machining operations required for a safe repair. Additionally, there is usually an absence of qualified welding and machining standards for field personnel to follow.
Since field repairs may result in significant down time, there is also an economic impact when removing a pipe section to replace a deformed wing nut. In manufacturing and drilling operations, down time directly impacts a company's cost of operations.
As identified herein, there is a need for a hammer union wing nut that does not require welding or machining. Additionally, there is a need for a field replaceable hammer union wing nut that may be easily and efficiently installed by field personnel.